pzel

type MaybeT[A] is (A|None)

primitive Maybe
  fun just[A: Any val](a: A) : MaybeT[A] => a
  fun nothing[A: Any val]() : MaybeT[A] => None
  fun fmap[A: Any val, B: Any val](v: MaybeT[A], f: {(A): B}): MaybeT[B] =>
    match v
    | None => None
    | let v' : A => f(v')
    end

pzel

class val Maybe[A: Any val] is Functor[A]
  let _v : (A | None)
  new val just(a: A) => _v = a
  new val nothing() => _v = None
  fun val fmap[B: Any val](f: {(A): B}) : Maybe[B] =>
    match _v
    | None => Maybe[B].nothing()
    | let v' : A => Maybe[B].just(f(v'))
  end

pzel

class val Maybe[A: Any val]
  let _v : (A | None)
  new val just(a: A) => _v = a
  new val nothing() => _v = None
  fun val fmap[B: Any val](f: {(A): B}) : Maybe[B] =>
    match _v
    | None => Maybe[B].nothing()
    | let v' : A => Maybe[B].just(f(v'))
  end

pzel

.setup: $(wildcard deps/**)
	@echo setting up
	@touch .setup

test: .setup
	@echo  tests ran

pzel

class Maybe[A : Equatable[A] val] is Equatable[Maybe[A]]
  let v : (A val | None)

  new val create(thing: A) => v = thing
  new val empty() => v = None
  
  fun eq(that: box->Maybe[A]): Bool =>
    match (this.v, that.v)
    | (let v' : A, let v'' : A) => v' == v''
    | (let n' : None, let n'' : None) => true

pzel

// This works
actor Router
  let _env : Env
  var _notifiers : Map[String val, ChatSession tag]

  new create(env: Env) =>
    _env = env
    _notifiers = Map[String val, ChatSession tag].create(10)

  fun ref _user_list() : Array[String] val =>

pzel

Unintiuitive behavior in String.strip()

I just ran across unintuitive behavior in [String.strip]

When the last U8 preceding the trailing whitespace is a fragment of a utf-8 sequence, it gets chopped off along with the following whitespace.
Whe the last U8 preceding the end of the string is a fragment of a utf-8 sequence, that last codepoint gets mangled to its first octet.

This goes against the prinicple of least surprise. Encoding issues notwithstanding,

pzel

%%% @doc Common Test Example Common Test Hook module.
-module(ct_tty_hook).

%% @doc Add the following line in your *.spec file to enable
%% reasonable, tty error reporting for your common tests:
%% {ct_hooks, [ct_tty_hook]}.

%% Callbacks
-export([id/1]).
-export([init/2]).

pzel

Project Build Tools: Output on first run vs. second run with no new changes

Cabal-install (Haskell), initial run:

Running cabal install for the first time, we get a full report of the steps taken to build the project.

hproject$ cabal install
Resolving dependencies...

pzel

p@maple:/usr/local/src/camping$ git diff
diff --git a/Gemfile b/Gemfile
index b0b1ee2..aee38c4 100644
--- a/Gemfile
+++ b/Gemfile
@@ -9,6 +9,12 @@ if rack = ENV['RACK']
   end
 end

+group :development do